Year	Percent
1990	35.139
1991	34.865
1992	37.109
1993	38.847
1994	39.002
1995	37.756
1996	38.236
1997	39.223
1998	40.136
1999	40.486
2000	39.503
2001	39.357
2002	39.499
2003	40.744
2004	43.413
2005	42.852
2006	43.837
2007	46.374
2008	48.322
2009	48.918
2010	52.876
2011	54.859
2012	55.306
2013	55.726
2014	56.398
2015	56.568
2016	57.045
2017	57.496
2018	57.944
2019	58.381
2020	58.804
2021	59.207
2022	59.594
2023	59.971
2024	60.346
2025	60.726
2026	61.107
2027	61.49
2028	61.876
2029	62.264
2030	62.654